Such a refrigerant compressor is known from, for example, DE 199 15 918 C2. A suction valve is fixed on the valve plate bottom side facing the compression chamber. A pressure valve is fixed on the opposite valve plate upper side, where it is located in a recess. A sealing is located between the cylinder adopting the compression chamber and the valve plate, and an additional sealing is located between the valve plate and the cylinder head cover. Together with a partition wall formed in the cover, this additional sealing ensures that the suction side and the pressure side are separated from each other. For this purpose, it is required that the complete cylinder head arrangement be assembled by means of screw bolts and fixed on the cylinder. In order to achieve a sufficient tightness, high tightening forces are required. Further, only narrow manufacturing tolerances are permitted. When the separation between the suction side and the pressure side is not realised satisfactorily, compressed, and thus hot, gas from the pressure side can reach the suction side, which reduces the efficiency of the compressor.
The tightening forces, which can be achieved with screws, are limited. Also, the forces, with which the parts forming the cylinder head are assembled, cannot in other ways be increased to a value exceeding a predetermined value, as this would cause a too high material strain.